Methods for making golf balls

ABSTRACT

A method of molding a layer of a reaction injection molding material about a golf ball component is disclosed. The method comprises holding a bottom portion of the component horizontally in a retaining cavity of retaining member to expose a top portion of the component; positioning the exposed top portion of the component in a top mold cavity of a top mold portion; molding a top portion of the layer from the material over the top portion of the component; disengaging the retaining member from the component to expose the bottom portion thereof; holding the molded top portion of the layer by the top mold portion; positioning the exposed bottom portion of the component in a bottom mold cavity of a bottom mold portion; molding a bottom portion of the layer from the material over the bottom portion of the component; and removing the golf ball product with the molded layer from the first and second molded portions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of co-owned and co-pending U.S. application Ser. No. 10/430,324, filed on May 7, 2003.

BACKGROUND

Golf balls are typically comprised of at least one cover layer that is compression molded, injection molded, or cast over a golf ball core. The golf ball core may comprise a liquid or solid center, and may further comprise one or more wound or solid layers. Individual layers, including outer core layers, intermediate layers, inner cover layers, and/or outer cover layers may be compression molded or injection molded.

Compression molding does not require supporting member for the core/subassembly or other components for introducing materials. Detailed features on compression-molded products, such as dimples on the golf ball cover, are in general significantly sharper than that of injection-molded products. However, compression molding may necessitate pre-production of the substantially spherical half shells, and pre-alignment of the half shells within the mold parts (e.g., mold halves) by hand or by machine. Furthermore, weak points may form at the parting line where the material of the two half shells melt and fuse together.

Injection molding is generally conducted in a closed mold cavity defined by multiple mold parts (e.g., two mold halves), in which the core/subassembly is positioned (e.g., centered) by a plurality of supporting members (e.g., fixed or retractable pins). Layer (e.g., cover) material in a flowable form (e.g., a reactive liquid material comprising multiple reactants, or a thermoplastic material melted at elevated temperatures) is injected under pressure (e.g., upwards of 12,000 psi) through multiple ports into the mold cavity, and the supporting members are removed (e.g., pins retracted), allowing the material to form a layer covering the entire core/subassembly. High injection pressure may deform the core/subassembly. Small air vents may significantly limit the injection speed. Weld or knit lines formed where the flowable material from different injection ports meet may result in discontinuities. Residual stress across the lines may results in poor finishes with poor definition of detailed features. Material failures (e.g., fractures) may occur at the lines following repeated use. Internal stress resulted from friction between the injected material and the inner surface of the mold and the core/subassembly may decrease homogeneity of the molded layer.

Casting also utilizes multi-part molds such as pairs of mold halves. The core/subassembly is positioned (e.g. by an overhanging vacuum or suction apparatus) and immobilized in a first portion of the castable material (e.g., a thermoset polyurethane or polyurea) in a first mold part. A second mold part carrying a second portion of the material joins the first mold part to form a closed mold cavity, and the castable material cures under heat and pressure to form the cover layer about the core/subassembly. Production rate may be limited by long curing time required for the castable materials to set for de-molding. Two-dimensional array of cavities used to boost production rate may poses additional technical challenges for processing. Long curing time may adversely impact flexural modulus and resiliency due to extended exposure to moisture or oxidation.

Reaction injection molding (“RIM”) is an alternative method suitable for forming golf ball layers from reactive liquids (e.g., polyurethane or polyurea). Conventional RIM involves injecting a highly reactive liquid material into a closed mold containing the core/subassembly, mixing under high pressure (e.g., 1,500-3,000 psi) in an in-line device (e.g., mixing head such as a “peanut mixer”) by way of impingement and/or mechanical mixing, and forming a coherent, one-piece molded layer over the core/subassembly. The reaction involved in the RIM process, often in the presence of a catalyst, may be substantially faster than that in the injection molding process. Both the mixing head and the mold are heated to reduce material viscosity for injection. RIM molding of golf ball outer cover layer has been demonstrated, for example, at K 2004 16^(th) International Trade Fair Plastics and Rubber in Düsseldorf, Germany, on Oct. 20-27, 2004, by Krauss-Maffei of Munich, Germany, using a RIM-STAR MiniDos machine. RIM processing still poses technical challenges for successful and efficient application, such as those related to simplifying mold design, perfecting the registration (i.e., centering) of the core/subassembly, reducing flash, and minimizing production cost.

SUMMARY

The methods disclosed herein are directed to molding a layer formed of at least one reaction injection moldable material about at least one golf ball product. The RIM material may be a flowable reactive material having a gel time of 10 seconds or less. One method may comprise holding a first (e.g., bottom) portion of the golf ball product in a retaining cavity of a retaining member to expose a second (e.g., top) portion of the golf ball product; positioning the exposed second portion of the golf ball product in a first (e.g., top) mold cavity of a first (e.g., top) mold portion; injecting the RIM material at a mating surface between the retaining member and the first mold portion into the first mold cavity to mold a first (e.g., top) portion of the layer over the second portion of the golf ball product; disengaging the retaining member from the golf ball product to expose the first portion thereof while holding the molded first portion of the layer by the first mold portion; positioning the exposed first portion of the golf ball product in a second (e.g., bottom) mold cavity of a second (e.g., bottom) mold portion; injecting the RIM material at a mating surface between the first and second mold portions into the second mold cavity to mold a second (e.g., bottom) portion of the layer over the first portion of the golf ball product; and removing the golf ball product with the molded layer from the first and second molded portions. The method may be used to mold a single golf ball, a plurality of balls aligned on a line, or a plurality of balls arranged in an A×B array of golf ball products where A and B are independent integers of at least 2. The retaining member array and the second mold portion array may be detachably affixed to a common mold platen and/or interleave with each other.

To hold the golf ball product in the retaining cavity, the golf ball product may be snuggly fitted in the retaining cavity that is substantially hemispherical and has a radius substantially equal to that of the golf ball product. The retaining cavity may be free of openings on its surface. Alternatively, the retaining member may comprise at least one through opening (e.g., two, three, or more through openings) in communication with the retaining cavity for air or inert gas to flow into or out of the retaining cavity (e.g., gap vents with stationary or retractable pins). A negative pressure may be applied to the retaining cavity via the through opening to help holding the golf ball product therein. Alternatively or in combination, one or more supporting members (e.g., retractable pins) may extend through the first mold portion into the first mold cavity to engage with the golf ball product, thereby holding it against the retaining member. To disengage the golf ball product from the retaining member, a positive pressure may be applied to the retaining cavity via the through openings. Alternatively or in combination, one or more supporting members may extend into the retaining cavity to expel the golf ball product out. Pneumatic or hydraulic means may be used to provide the negative and/or positive pressures. The pneumatic means and the retractable elements may be used alone individually or in combination thereof.

The first mold cavity may be free of openings on its surface. Alternatively, the first mold portion may comprise at least one through opening (e.g., two, three, or more through openings) in communication with the first mold cavity for air or inert gas to flow into or out of the first mold cavity. A negative pressure may be applied to the first mold cavity via the through opening to help holding the golf ball product therein. Alternatively or in combination, one or more supporting members may extend through the second mold portion into the second mold cavity to engage with the golf ball product, thereby holding it against the first mold portion. To remove the molded layer from the first mold portion, a positive pressure may be applied to the first mold cavity via the through openings. Alternatively or in combination, one or more supporting members may extend into the first mold cavity to expel out the molded golf ball product. Pneumatic or hydraulic means may be used to provide the negative and/or positive pressures. The pneumatic means and the supporting members may be used alone individually or in combination thereof.

The second mold cavity may be free of openings on its surface. Alternatively, the second mold portion may comprise at least one through opening (e.g., two, three, or more through openings) in communication with the first mold cavity for air or inert gas to flow into or out of the first mold cavity. To remove the molded layer from the second mold portion, a positive pressure may be applied to the second mold cavity via the through openings. Alternatively or in combination, one or more supporting members may extend into the second mold cavity to expel out the molded golf ball product. Pneumatic or hydraulic means may be used to provide the positive pressure. The pneumatic means and the supporting members may be used alone individually or in combination thereof.

The retaining member may be stationary or mobile. The retaining member may be mobile but independent of the second mold portion (i.e., the two do not move together). At least one (e.g., two, or all three) of the retaining member, the first mold portion, and the second mold portion may be detachably affixed to at least one of the first and second mold platens. To enhance the adhesion of the first and second molded portions of the layer, the two portions may overlap at one or more locations with a width of 0.005 inches or greater. The molded layer may be an outer cover layer, an inner cover layer, an intermediate layer, a dimpled layer, a lattice network layer, a discontinuous layer comprising a plurality of discrete elements, or a combination thereof. The molded layer may have a thickness of 0.03 inches or less.

DESCRIPTION OF DRAWINGS

Various features of the present disclosure are illustrated in FIGS. 1-25 as described below, but are not limited thereto. These features may stand alone, or be used in any combination of two or more thereof. Disclosure of the features herein, their utilization, and their combinations, are not limited by these exemplary figures. Briefly,

FIG. 1 illustrates a perspective view of an exemplary set of mold portions;

FIG. 2 illustrates a cross-sectional diagram of the mold of FIG. 1 in a first closed position;

FIG. 3 illustrates a cross-sectional diagram of the mold of FIG. 1 in a partially open position;

FIG. 4 illustrates a cross-sectional diagram of the mold of FIG. 1 in a second closed position;

FIG. 5 illustrates a perspective view of another exemplary mold portion;

FIG. 6 illustrates a perspective view of a further exemplary mold portion;

FIG. 7 illustrates a cross-sectional view of a retractable pin molding device;

FIG. 8 illustrates a front view of a molding apparatus in a first open position;

FIG. 9 illustrates a side view of the mold apparatus of FIG. 8 in the first open position;

FIG. 10 illustrates an example of a first mold platen used in the mold apparatus of FIG. 9;

FIG. 11 illustrates an example of a second mold platen that corresponds to the first mold platen of FIG. 10;

FIG. 12 illustrates a front view of the mold apparatus of FIG. 9 in a first closed position;

FIG. 13 illustrates a cross-sectional diagram of a retaining member and a first mold portion prior to reaction injection molding;

FIG. 14 illustrates a cross-sectional diagram of the retaining member and the first mold portion of FIG. 13 during reaction injection molding;

FIG. 15 illustrates a cross-sectional diagram of the retaining member and the first mold portion of FIG. 13 immediately after reaction injection molding;

FIG. 16 illustrates a front view of the mold apparatus of FIG. 9 in a second open position;

FIG. 17 illustrates a front view of the mold apparatus of FIG. 9 in a second closed position;

FIG. 18 illustrates a cross-sectional diagram of a first mold portion and a second mold portion prior to reaction injection molding;

FIG. 19 illustrates a cross-sectional diagram of the first and second mold portions of FIG. 18 during reaction injection molding;

FIG. 20 illustrates a cross-sectional diagram of the first and second mold portions of FIG. 18 immediately after reaction injection molding;

FIG. 21 illustrates another example of a first mold platen;

FIG. 22 illustrates an example of a second mold platen that corresponds to the first mold platen of FIG. 21;

FIG. 23 illustrates a further example of a first mold platen;

FIG. 24 illustrates an example of a second mold platen that corresponds to the first mold platen of FIG. 23; and

FIG. 25 is a perspective view of a golf ball component covered with a layer of a lattice network in the form of a spherical octahedron.

DESCRIPTION

As used herein, the term “active hydrogen-containing compound” refers to any one compound or mixture of two or more compounds wherein each molecule comprises one, two, three, four, or more of the same or different primary and/or secondary groups each comprising one or more active hydrogen atoms, such as —OH (hydroxyl group), —NHR (amine group where R can be hydrogen, alkyl, aryl, or alicyclic groups), —SH (thio group), and —COOH (carboxylic acid group). These active hydrogen groups are reactive to free reactive iso(thio)cyanate (i.e., isocyanate and/or isothiocyanate) groups, forming urethane, urea, thiourethane, thiourea, and/or other corresponding linkages. As such, all active hydrogen-containing compounds, including monoahls and polyahls, are iso(thio)cyanate-reactive compounds, although not all iso(thio)cyanate-reactive compounds are active hydrogen-containing compounds. Oligomeric and polymeric polyahls may also be referred to as telechelic polyahls.

As used herein, the term “saturated” or “substantially saturated” means that the compound or material of interest is fully saturated (i.e., contains no double bonds, triple bonds, or aromatic ring structures), or that the extent of unsaturation is negligible, e.g. as shown by a bromine number in accordance with ASTM E234-98 of less than 10, such as less than 5.

Other than in the operating examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials, times and temperatures of reaction, ratios of amounts, values for molecular weight, and others in the following portion of the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values inclusive of the recited values may be used.

As used herein, the terms “formed from” and “formed of” denote open, e.g., “comprising,” claim language. As such, it is intended that a composition “formed from” or “formed of” a list of recited components be a composition comprising at least these recited components, and can further comprise other non-recited components during formulation of the composition.

As used herein, the term “cure” as used in connection with a composition, e.g., “a curable material,” “a cured composition,” shall mean that any crosslinkable components of the composition are at least partially crosslinked. In certain examples of the present disclosure, the crosslink density of the crosslinkable components, i.e., the degree of crosslinking, can range from 5% to 100% of complete crosslinking. In other examples, the crosslink density can range from 35% to 85% of full crosslinking. In other examples, the crosslink density can range from 50% to 85% of full crosslinking. One skilled in the art will understand that the presence and degree of crosslinking, i.e., the crosslink density, can be determined by a variety of methods, such as dynamic mechanical thermal analysis (DMTA) in accordance with ASTM E1640-99.

Broadly, the present disclosure is directed to an apparatus for and a method of making a solid layer in a golf ball. The apparatus and the method involve a RIM process, and the solid layer is formed from thermoset or thermoplastic materials such as polyurethanes and polyureas. Such a RIM-formed layer can be used as an outer cover, or to provide a transition between a soft outer cover layer and a hard inner cover layer, thereby allowing the ball designer a means to tune the spin rate profile for medium to short iron play. Alternatively, as an inner cover layer, the RIM-formed layer can also act to reduce driver spin rates while maintaining wedge spin rates. Application of such a RIM-formed layer is not limited in the cover only. For example, the RIM-formed layer may be used in the core, such as an outer core layer, or in between the core and the cover, as an intermediate layer or a barrier layer.

Furthermore, the RIM-formed layer may be a continuous layer such as a spherical shell or a spherical lattice network, or a discontinuous layer having a plurality of discrete elements (e.g., islands) that are uniformed or non-uniformed, having the same or different size, shape (e.g., circles, triangles, hexagons), and thickness. The RIM-formed layer may cover at least 10%, such as at least 30%, and up to 100% of the surface area of the underlying golf ball precursor or component (e.g., core or subassembly). When the RIM-formed layer is a lattice network, it can be of any shape and form, such as having at least three bands extending along great circle paths of the underlying golf ball component. The bands along great circle paths may form a spherical Platonic or Archimedean solid.

The golf ball may be a two-piece ball, a three-piece ball, a four-piece ball, a multi-layered having five or more pieces, or a wound ball having at least one layer comprised of a tensioned elastomeric material, having different combinations of cores, intermediate layers, covers and/or coatings. A “cover” or a “core” as these terms are used herein includes a structure comprising either a single mass or one with two or more layers. As used herein, a core described as comprising a single mass means a unitary or one-piece core. The layer thus includes the entire core from the center of the core to its outer periphery. A core, whether formed from a single mass, two or more layers, or a fluidic (e.g., liquid-filled, gas-filled, gel-filled) center may serve as a center for a wound ball or a solid ball. An intermediate layer may be incorporated, for example, with a single layer or multi-layer cover, with a single mass or multi-layer core, with both a single layer cover and core, or with both a multi-layer cover and a multi-layer core. Intermediate layers may include outer core layers, inner cover layers, outer core layers, and mantle layers.

Referring now to the figures, a discussion of the features disclosed herein with respect to exemplary embodiments is provided. It should be understood that such embodiments are for illustrative purposes, and should not be construed as limiting the scope of the disclosure. The methods disclosed herein may be used to mold a layer of thermoplastic or thermoset material, such as polyurethane, polyurea, or polyurethane/polyurea hybrid around a golf ball component.

FIGS. 1 and 2 illustrate a golf ball component 10 and a mold 12. Component 10 may be a golf ball core, such as a single-piece solid core, or a core comprise a center and one or more outer core layers. The center may be solid, gas-filled, liquid-filled, gel-filled, or hollow. The outer core layers may independently be solid, wound, continuous, discontinuous, or in a lattice network form. Component 10 may also be a subassembly comprising a core and one or more additional layers, such as wound layers, intermediate layers, barrier layers, mantle layers, and/or inner cover layers. Mold 12 may have two substantially similar parts 14, each having an inner surface 22 that is a portion of a substantial sphere (e.g., substantially hemispherical), and a mating surface 18 (e.g., substantially circumferential, planar, non-planar, tooth-form, step-form, sinusoidal, etc.). Inner surface 22 defines a cavity 16 that is a portion of a substantial sphere (e.g., a substantial hemisphere). Mating surfaces 18 may have complementary configurations that may be inter-locking and self-aligning, such that when they are brought together to be in contact with each other, mold 12 is closed, forming a shell-shaped void 20 between mold portions 14 and component 10.

In one example, component 10 is substantially centered in cavities 16 (i.e., component 10 and cavities 16 being concentric with each other), so that void 20 has a substantially uniformed thickness. The RIM process is capable of molding layers or covers of thickness of at least 0.0005 inches, and up to 0.2 inches, such as 0.001 inches, 0.0015 inches, 0.002 inches, 0.003 inches, 0.0035 inches, 0.005 inches, 0.0075 inches, 0.01 inches, 0.02 inches, 0.03 inches, 0.05 inches, 0.1 inches, and any numbers or ranges therebetween. In another example, the RIM process form an inner cover layer, an intermediate cover layer, an outer cover layer, or a cover, the layer having a dimple pattern. Inner surfaces 22 may have a negative dimple pattern with multiple protrusions 23 that form dimples in the molded layer. Some or all of protrusions 23 may have a concave profile and a shape that is substantially circular, non-circular (e.g., oblong, ellipse), or polygonal (e.g., triangular, square, pentagonal, hexagonal, octagonal). Some of protrusions 23 may feature a convex profile. Some of protrusions 23 may have a profile featuring one or more (e.g., 2, 3, or more) concave portions and one or more (e.g., 2, 3, or more) concave portions. Protrusions 23 may have various cross-sectional curvatures that complement the desired dimple profiles, which include, without limitation, circular curves, parabolic curves, ellipses, semi-spherical curves, saucer-shaped curves, sinusoidal curves, truncated conical curves, flattened trapezoidal curves, as well as catenary curves disclosed in U.S. Pat. No. 6,796,912, which is incorporated herein by reference in its entirety.

One or more of mold portions 14 may incorporate one or more positioning members 28 to hold, at least in part, component 10 in a predetermined position (e.g., being concentric to inner surfaces 22). In one example, the positioning member 28 comprises one or more (e.g., 2, 3, 4, 5, 6, 7, 8, 10, or 2n where n is integer of 1-10) retractable pins extendable through each mold portion 14 into cavity 16. Tip surfaces 33 of positioning member 28 may engage (i.e., be in contact) with the outer surface of component 10, and may be fashioned to comprise less than one, one, or more (e.g, 1.5, 2, 2.5, 3, or more) protrusions 23, so as to form dimples in the molded layer. Other types of positioning members 28 known to one skill in the art may also be employed in alternative embodiments.

Each mold portion 14 may further comprise at least one (e.g., two or more) vent pin 24 (fixed or retractable) that extends mold portion 14 to inner surface 22. The diameter of vent pins 24 may be slightly smaller than that of surrounding bores 26 to provide therebetween a tubular gap vent 27. The gap may be 0002 inches to 0.0005 inches in width. Vents 27 thus communicate void 20 with the exterior space for venting air during molding cycles, particularly while mold 12 is in closed positions. Tip surfaces 31 of vent pins 24 may be fashioned to comprise less than one, one, or more (e.g, 1.5, 2, 2.5, 3, or more) protrusions 23.

Mold 12 may have 1-10 (e.g., 2, 3, 4, 5, 6, 8, etc.) injection gates 29. Each injection gate may be configured independently to receive an injection nozzle 30. Alternatively, a single nozzle 30 may be connected to two, three, four, or more, or all injection gates, through a runner system. Gates 29 may be spaced at equal angle and equal distance from each other around mating surfaces 18. In one example, four injection gates 29 may be spaced at about 90 degrees from each other. Nozzles 30 may seat tightly in injection gates 29 when mold 12 is open or closed. Injection gates 29 may be in communication with cavities 16 when mold 12 is open, or in communication with void 20 when mold 12 is closed, or both. Alternatively, nozzles 30 may be moved into gates 29 after mold 12 is closed.

Nozzles 30 may be configured to inject a reactive liquid material 32 that forms the desired layer. Reactive liquid material 32 may comprise at least two reactants that form a thermoset or thermoplastic polymer such as polyurethane, polyurea, epoxy, or unsaturated polyester. The first reactant may comprise an isocyanate, a polyisocyanate, an isocyanate-containing prepolymer, or an isocyanate-containing quasi-prepolymer. The prepolymer or quasi-prepolymer may be an adduct of a polyisocyanate (e.g., a single polyisocyanate or a blend of two or more polyisocyanates) with a polyahl (e.g., a single polyol and/or polyamine, or a blend of two or more polyols and/or polyamines) or epoxy-containing compound, or a blend of two or more of such adducts. The second reactant may comprise at least one curing agent, such as a single polyahl or epoxy-containing compound, or a blend of two or more thereof.

Conventional additives for reactive liquid material 32 include, but are no limited to, crosslinking agents, catalysts, fillers, accelerators, processing aids, processing oils, plasticizers, foaming agents, colorants, radical quenchers, as well as other additives known to one of ordinary skill in the art. Suitable polyisocyanates, polyols, polyamines, epoxy-containing compounds, additives and other materials for reactive liquid material 32 include those described in co-owned U.S. Pat. Nos. 5,484,870, 6,083,119, 6,386,992, 6,610,812, and 6,645,088, as well as co-pending U.S. patent application Ser. No. 10/859,537, the disclosures of which are incorporated by reference in their entirety.

The reactants in their liquid form may be stored in separate tanks and preheated to 90-150° F. prior to the RIM process. Additives may be pre-mixed with one or both reactants and transferred into the storage tanks. The reactants may be metered in the desired weight ratio and fed into a mix head where mixing of the reactants occur under a hydraulic pressure P_(i) (e.g., 1,000 psi, 1,500 psi, 3,000 psi, 5,000 psi, or any ranges therebetween). Alternatively, the additives may be stored in tanks separate from the two reactants, and added directly into the mix head during the mixing process. The mix head can be an in-line device such as a peanut mixer, or a mixing chamber integrated within the mold. Other methods of mixing (e.g., mechanical mixing) and designs of mix heads are well know to one of skill in the art of liquid mixing. Upon thorough mixing, the mixture of the reactants can be rapidly injected into mold 12. Reactive liquid material 32 polymerizes to form a coherent, one-piece molded layer about component 10. Both the mix head and mold 12 may be heated to ensure proper viscosity of material 32 for injection.

As illustrated in FIG. 2, prior to injecting material 32, mold portions 14 may be held together in a closed injection position, optionally by a hydraulic press (not shown) under a injection tonnage T_(i) (e.g., 10 kN, 20 kN, 40 kN, 60 kN, 80 kN, 100 kN, or any ranges therebetween). The molding device may include 1 mold set, such as 2, 4, 6, 8, 10, or more mold sets. Material 32 may be injected into mold 12 under hydraulic pressure P_(i) sufficient to overcome holding tonnage T_(i). The hydraulic pressure P_(i) may separate mold portions 14 by an opening 38 (see FIG. 3), and holding mold 12 in a partially open injection position. Hydraulic pressure P_(i) may be adjusted to control the size of opening 38 and consequently the injection speed of material 32. Opening 38 may be large enough to vent air rapidly from void 20 during injection to prevent buildup of intra-cavity pressures and slowdown of injection, while small enough to contain material 32 within void 20 and prevent material 32 from flashing through. Other factors to be considered when determining P_(i) include, among others, laminar and turbulent flows, air bubble generation, fluid viscosity and reaction rate of material 32. Opening 38 may be at least 0.001 inches, such as 0.002 inches, 0.005 inches, 0.01 inches, 0.015 inches, or any ranges therebetween. Opening 38 may be maintained throughout the entire injection process, as fronts 40 of material 32 moving through and fill void 20. When a sufficient amount of material 32 has been injected into void 20 to hold component 10 substantially in the predetermined position, positioning member 28 can disengage component 10 and retract out of void 20.

The injection may continue, or stop, as long as sufficient amount of material 32 has been injected in void 20 to flow around component 10, displacing the air and filling the remaining portions of void 20 left by the retracted positioning member 28, while the air vents at least in part from opening 38. Where fronts 40 contact each other, weld lines may form, and material 32 may be discontinuous across the weld lines. At the same time, material 32 may rapidly cure into a gel or semi-solid form.

Referring to FIG. 4, mold portions 14 may be compressed towards each other under a compression tonnage T_(c), which may be exerted by the same hydraulic press or some other mechanism, to close opening 38 and bring mold 12 to a closed compression position. The partially cured material 32 may be compression molded into the desired layer about component 10. Compression tonnage T_(c), may be greater than injection tonnage T_(i), such as by at least 20% in magnitude, or being twice as much in magnitude, or even greater, or somewhere therebetween. Alternatively, hydraulic pressure P_(i) can be removed to allow injection tonnage T_(i) to close mold 12, thereby initiating compression molding without exerting T_(c). The compression molding process may commence once sufficient amount of material 32 has been injected to fill void 20, such as at least 40% by volume, at least 50% by volume, or at least 80% by volume. Little or no further injection of material 32 may be necessary once mold 12 is closed under T_(c) or upon cessation of P_(i).

The compression molding process relieves a significant portion of the internal stress within mold 12, including the stress at weld lines and the frictional stress between component 10 and inner surfaces 22. The compression molding process may fuse material 32 at weld lines, thereby significantly reducing imperfections in the molded layer (e.g., discontinuities at the weld lines). The compression molding process may also aid in the release of the molded layer from mold 12. In processes where positioning members 28 (e.g., retractable pins) are used, the compression molding process may also close voids left by positioning members 28. The compression molding process may pack in material 32 tightly and completely into detailed features in void 20, such as corners around protrusions 23, thereby enhancing the definition and aesthetics of the molded product.

During the compression molding process, mold 12 may be maintained at a substantially constant temperature between 40° F. and 90° F., such as at about 50° F. This can be achieved by circulating a fluid (e.g., cool water) around mold 12, or through enclosed passages within mold 12, or both. If reactive liquid material 32 forms a thermoplastic polymer, this temperature may be below the polymer's melting point so that the polymer quickly solidifies within mold 12. The de-molding (i.e., releasing) process comprises removing the molded product (i.e., component 10 covered by the molded layer) as a whole from mold 12 after it is opened.

In another example, mold 12 may be held open with a predetermined opening 38 prior to injecting material 32 into void 20. The reactants of material 32 may be heated in their respective reservoir tanks, and then forced into the mix head under the same or different hydraulic pressures P_(i). Nozzles 30 and the optional runner system may be maintained above the highest melting temperature of all reactants, while mold 12 may be maintained below the melting temperature of material 32. The optional runner system, when present, may reduce, if not eliminate, any sprues attached to the molded layer.

FIGS. 5 and 6 illustrate high-throughput mold portions 42 and 44 that are alternatives to mold portions 14. Mold portions 42 and 44 are configured to mate with similar or corresponding mold portions to form two-ball molds. Mold portion 42 may employ a hot-to-cold runner system. Nozzle 46 can be placed against mold portion 42 to inject material 32 through internal, hot runner 48 within mold portion 42 to a cold runner 50 (e.g., planar runner disposed substantially on the mating plain of mold portions 42). Runner 50 may in turn feed multiple (e.g., ten) injection gates 52 surrounding each partial mold cavity 54. Mold portion 44 may use a cold runner system. Material 32 may be injected through nozzle 56 directly into a cold runner system 58 (e.g., planar runner disposed substantially on the mating plain of mold portions 44). Runner 58 may feed multiple (e.g., ten) injection gates 52 surrounding each partial mold cavity 59.

The molding process disclosed above may reduce residual stress within the molded layer, enhance material homogeneity within the molded layer, strengthen the weld lines, and enable easy release of the molded balls from the molds. The molding process may also improve adhesion between the molded layer and the underlying component, and achieve better concentricity between the two (i.e., improve registration). The molding process may further sharpen or otherwise enhance detailed features on the molded layer, thereby improving its aesthetic appearance. The open mold design may allow rapid air venting, thereby shortening injection time and reducing the hydraulic pressure P_(i).

FIG. 7 illustrates a cross-sectional view of an exemplary retractable pin reaction injection molding device 100, which may comprise mold portions 14 that cooperate to form at least one mold 12. Each mold portion 14 may have at least one inner surface 22 that defines at least one cavity 16 (e.g., hemispherical). Cavities 16 can mate to form a cavity (e.g., spherical) when mold portions 14 are mated at mating surface 18. Mold portions 14 may also have additional cavities to cooperatively form one or more cavities 29, which can be used as outlets for evacuation purposes. Mold portions 14 may be arranged in a horizontal orientation as illustrated, and referred to as top and bottom mold portions. Alternative, mold portions 14 may be arranged in a vertical orientation and referred to as right and left mold portions or front and back mold portions. Arrangements of other orientations known to one skilled in the art may also be suitable for mold portions 14.

Molding device 100 may further comprise one or more (e.g., 2, 3, 4, 5, 6, 7, 8, 10, or 2n where n is integer of 1-10) retractable pins 28, such as the four illustrated in FIG. 7. At the initial stage of the RIM process, or prior to that, golf ball component 10 may be placed in cavities 16. Component 10 may be held by pins 28 extended into cavities 16, such as being centered to form at least one substantially spherical shell-shaped void 20 between component 10 and mold inner surfaces 22. Component 10 may be at any stage of manufacturing, such as a core, or a core with one or more layers already formed thereon. The orientation of pins 28 may be the same or different, such as being vertical as illustrated (i.e., being perpendicular to mating surface 18), being horizontal (i.e., being parallel to mating surface 18), or being at any angle of 0-90 degrees (e.g., 15, 30, 45, 60) to mating surface 18. Pins 28 may be affixed to plates 35, which control the movement of pins 28 (e.g., engaging and disengaging component 10 or the molded layer). Plates 35 may be actuated in a variety of manners known within the art, such as hydraulically or pneumatically. Seals 34 (e.g., O-rings) may be used in conjunction with pins 28 to prevent matter (e.g., material 32, moisture) from entering or exiting mold 12. Stops 36 may be used to limit outward travel of plates 35.

After pins 28 have engaged with component 10, material 32 may be injected into mold 12. Reservoirs such as tanks 70 may house two or more components that, upon mixing (e.g., impingement mixing), cooperate to produce the layer-forming material 32. Tanks 70 may be connected by flow lines 71 to at least one channel 75 within housing 74. Channel 75 may provide a pathway for material 32 into void 20. A plunger 72 may be movably retained within housing 74. Plunger 72 may be movable between an inserted position, in which plunger 72 covers lines 71 and prevents components of material 32 from entering channel 75, and a retracted position (as illustrated), in which plunger 72 does not cover lines 71 and allows the components of material 32 to enter channel 75.

Components of material 32 may be drawn from tanks 70 by open cylinders 77 and properly oriented valves 78 (e.g., 3-way valves). Once a predetermined amount of the components have been removed from tanks 70, or once a predetermined amount of time for drawing the components has elapsed, valves 78 can be reoriented to connect cylinders 77 to channel 75. Cylinders 77 may then be closed, forcing the components in lines 71 into channel 75. The pressure (e.g., 25 kpsi, or greater, or less) at which the components are injected into channel 75 and into mold 12 may be determined at least in part by the force applied by cylinders 77 and the size of lines 71. Nozzles 30 may optionally be placed between lines 71 and channel 45 to assist impingement mixing of the components. Pumps (e.g., gear pumps) can be used in place of, or in addition to, cylinders 77.

Upon movement of plunger 72 from the inserted position to the retracted position, lines 71 become uncovered. The drawn components in lines 71 can impinge upon each other within channel 75 and mix together into material 32. The pressure created by cylinder 77 that force the components into channel 75 may also force the mixed material 32 into void 20. The relatively low viscosity material 32 may flow into the clearance around pins 28 and other crevices within and between mold portions 14. A single injection gate 29 or a plurality of injection gates 29 may be used to evenly distribute material 32 around component 10. Injection gates 29 may be located at the parting line of mold 12 (i.e., mating surface 18). Channel 75 within housing 74 or within mold 12, or both, may directly extend into mold 12, or optionally include one or a number of runners and/or gate flippers to maintain uniformity and thermal balance of material 32, as described in U.S. Pat. No. 6,235,230, the disclosure of which is incorporated herein by reference in its entirety.

A counterpressure of gas may be used to prevent material 32 from entering and fouling pin holes of pins 28 in mold portions 14. This gas may be provided by tank 82, or a pump, or the likes thereof. Inert gas such as helium, or diatomic gas such as nitrogen, or compressed air, may be used. Lines 81 may provide conduits for the gas to flow into mold 12. A pressurizer 83 can maintain a predetermined pressure within lines 81. A dehumidifier 84 may optionally be used to remove moisture from the gas within lines 81. A valve 85 can control the flow of gas within lines 81. Valve 85 may be placed in an open position to allow flow through lines 81, in a closed position to prevent flow through lines 81, or in an intermediate position between open and closed positions to throttle flow through lines 81. A timer 86 may optionally be included to automatically control the operation of valve 85. Lines 81 may travel within mold portions 14 and empty into the pin holes of pins 28. Seals 34 may prevent the gas from flowing out of mold 12 along pins 28. The gas can flow through the clearance around pins 28 and into void 20.

A method of using the device 100 to mold a layer over component 10 may involve any number of the following steps, the order of which is not limited herein. Two or more steps may take place at the same time, or temporally overlap. At one step, component 10 can be held by pins 28 within cavities 16 in known fashion. Reactive and/or non-reactive components of material 32 can be placed in tanks 70 and held therein. At another step, plunger 72 can be moved to the retracted position, opening lines 71 into channel 75. At another step, cylinders 77 and valves 78 can be operated to draw the components from tanks 70 and inject them into channel 75, which can serve at least as a part of a mixing chamber where the components impinge upon each other and thereby mix. At another step, the mixed material 32, pressurized by cylinders 77, can be propelled into cavities 16 and fill void 20, while trapped air and/or gases can escape through vents in known manner (e.g., vent pins 24). Other alternative vents may be located opposite to injection gates 29 along the parting line (e.g., mating surface 18). Since material 32 is mixed immediately before being inserted into void 20, it can have a viscosity of 5,000 cps or less (e.g., 3,000 cps, 2,500 cps, 2,000 cps, 1,500 cps, 1,000 cps, or less), a gel time of 15 seconds or less (e.g., 10 seconds, 5 seconds, 3 seconds, 2 seconds, 1 second, 500 milliseconds, 300 milliseconds, 200 milliseconds, 100 milliseconds, or less, or any ranges therebetween), and/or being thermoset or thermoplastic.

At another step, once void 20 has been substantially filled but before material 32 has completely hardened, pins 28 can be retracted from cavities 16 until tip surfaces 33 form a portion of inner surfaces 22 of mold 12 (see FIGS. 2-4). When pins 28 are retracted after being contacted by material 32, voids left by the retracted pins 28 can be filled by material 32. Cavity surface 22 and pin faces 33 (see FIG. 1) may include protrusions that cooperate to form a dimpled pattern on the outer surface of the molded layer. Each pin face 33 may comprise less than one, one, or more (e.g, 1.5, 2, 2.5, 3, or more) dimple-forming protrusions thereon.

At another step, after a predetermined amount of time has lapsed since material 32 enters void 20, valve 55 can be opened to engage the counterpressure gas system, allowing gas from tank 82 to flow through lines 81. Dehumidifier 84 may optionally be used to ensure that the gas does not carry moisture into mold 12. The gas may flow into void 20 initially, until enough of material 32 has entered void 20. Pressurizer 83 can maintain a predetermined pressure within lines 81 to counter the injection pressure of material 32, allowing material 32 to only flow into void 20 and contact inner surface 22 in its entirety, but not flow into the clearance between pins 28 and mold 12, thereby minimizing or eliminating post-mold flash removal and/or pin hole cleaning. The predetermined pressure is based in part upon the injection pressure and properties (e.g., viscosity) of material 32. Excess of material 32 and trapped gas are vented into cavity 29.

At another step, after a predetermined amount of material 32 has been injected into void 20, plunger 72 may be returned to the inserted position to prevent further components of material 32 from entering into channel 75, and force remaining material 32 within channel 75 into mold 12. At another step, after a predetermined amount of time has lapsed since plunger 72 is returned to the inserted position, valve 85 can be closed to disengage the counterpressure gas system. A pressure-relief valve may be provided in lines 81 between valve 85 and mold 12 to relieve remaining pressure within lines 51. At another step, after the injected material 32 has substantially hardened, mold 12 is opened to release the molded golf ball product. As used herein, golf ball product refers to a golf ball at any stage of manufacture, such as a subassembly having a mantle layer over a core, a golf ball having a cover layer over a core, or golf ball having a cover layer over the subassembly.

The counterpressure gas system may be engaged prior to pins 28 being retracted or prior to material 32 entering void 20. When initiated immediately before or after material 32 is injected, the same gas system may be used to balance and/or control the flow of material 32 into and through mold 12. The equalizing pressure of the gas system negates any filling imbalances caused by, for example, thermal or viscosity difference in the material streams, and ensures a balanced fill throughout void 12, which may be an issue when each mold portions 14 has multiple (e.g., 2, 3, 4, 5, 6, or more) molding cavities 16.

FIGS. 8 and 9 illustrate a molding device 200, comprising a linear cylinder 102 (e.g., motor-driven, hydraulic, or pneumatic) having at least one extendable inner rod 106. The outer body of cylinder 102 may be affixed to a plate 104, which may be affixed to rods 108, which may be affixed to plate 114, which may be affixed to plate 116, which may be affixed to posts 126, which may be affixed to plate 132. These parts may be made stationary. Affixation means include, but are not limited to, fasteners such as nuts/bolts, adhesives, and welding. Inner rod 106 may be affixed to plate 110, which may be affixed to rods 112, which may be affixed to plate 130. Via through bores (not shown), rods 112 can slide through plates 114 and 116, and plate 130 can slide along posts 126. At least one (e.g., 2, 3, or more) of a first (e.g., top) mold platen 118 may be affixed to plate 116 (e.g., docked in a recess therein, or partially or fully embedded therein). At least one (e.g., 2, 3, or more) of a second (e.g., bottom) mold platen 124 may be supported by plate 130. Mold platen 124 may be docked in a recess 128 fashioned on a top portion of plate 130 as illustrated, so that mold platen 124 is movable with at least one (e.g., 2, 3, or more) degree of freedom. Movements with one degree of freedom include one-dimensional movements, such as linear movements and translational movements. Movements with two degrees of freedom include two-dimensional movements. Movements with three degrees of freedom include three-dimensional movements. With respect to plate 130 and within recess 128, mold platen 124 may be capable of translational movements along a horizontal line in two opposite directions (i.e., linear movements), or on a horizontal plain in any direction (i.e., two-dimensional movements). Movements (e.g., horizontal) of mold platen 124 may be effected by manual means (e.g., via T-shaped attachments comprising handle bars 120 and rods 122), mechanical means (e.g., linear or planar actuators, step motors, and the likes), hydraulic means (e.g., hydraulic cylinders), pneumatic means (e.g., pneumatic cylinders), or combinations of two or more of such means. Movements of mold platen 124 may be facilitated by applying friction-reducing means on the contacting surfaces between mold platen 124 and plate 130, such as lubricants, rolling pins, ball bearings, and the likes.

Mold platen 118 may comprise or carry at least one of a first (e.g., top) mold portion 14 having a first cavity 16. Mold platen 124 may comprise or support at least one of a second (e.g., bottom) mold portion 90 having a second cavity 92, and at least one of a retaining member 96 having a retaining cavity 98. Mold portions and retaining members may be detachably affixed to mold platens, such as being docked (e.g., snuggly fitted) in a recess or cavity or through opening therein (e.g., partially or fully embedded therein), optionally by mechanical means (e.g., screws, clamps, retractable pins, threads, and the likes or combinations thereof), magnetic means (e.g., embedded permanent magnets or switchable electrical magnets), suction means (e.g., vacuum or negative pressure suction), or any other means known to one skilled in the art of engineering. Combinations of two or more means may be used. Prior to molding, inner rod 106 of cylinder 102 may be extended, leaving mold platens 118 and 124 separated in a first open position (i.e., the beginning position). Component 10 (e.g., a golf ball product) may be retained in retaining cavity 98 (i.e., securely placed and immobilized therein, or snuggly fitted therein), which may have at least one radius substantially equal to the radius of component 10 (i.e., greater or less than the radius of component 10, with a difference of 0 to no more than 0.005 inches, or no more than 0.002 inches, or no more than 0.001 inches). Optionally, retaining cavity 98 may have one or more openings through retaining member 96, and component 10 may be held in retaining cavity 98 by hydraulic or pneumatic suction applied through such openings.

FIG. 10 illustrates an example of mold platen 118 having mold portion 14 docked therein, with mold cavity 16 connected on one side to injection gate portion 29 a via channel 75, and on another side to vent cavity 19. FIG. 11 illustrates an example of mold platen 124 having mold portion 90 docked therein, with mold cavity 92 connected on one side to injection gate portion 29 c via channel 95, and on another side to vent cavity 91. Mold platen 124 further has retaining member 96 docked therein, with retaining cavity 98 disconnected from injection gate portion 29 b. Gate portion 29 c, channel 95, mold portion 90, and vent cavity 91 may be configured to correspond to (e.g., being able to mate with) gate portion 29 a, channel 75, mold portion 14, and vent cavity 19, respectively. Gate portion 29 b and retaining member 96 may be configured to correspond to gate portion 29 a and mold portion 14, respectively. Channels 75 and 95 may be fashioned to enhance mixing of materials flowing therein. Other channel designs capable of facilitating fluidic mixing may be used herein, such as those incorporate multiple turning points and/or bifurcation points.

Mold cavities 16 and 92 may substantially be a portion of a sphere (e.g., caps, zones, lunes, hemispheres). Mold cavities 16 and 92 may mate together to form a substantially spherical cavity, and each may be substantially hemispherical. The inner surfaces of mold cavities 16 and 92 may be substantially smooth, or have multiple protrusions and/or indentations that are the same or different (e.g., in profile, size, shape, curvature, height, depth). Suitable protrusions include those disclosed herein. Retaining cavity 98 of retaining member 96 may have an inner surface substantially complementary to a portion of the outer surface of a golf ball product, such as being substantially a zone or a hemisphere, so that the product can be snuggly fitted into retaining cavity 98. In one example, retaining cavity 98 may be substantially smooth and spherical (e.g., hemispherical, or a portion thereof), and has a radius less than that of mold cavities 16 and 92.

Mold portions 14 and 90 may have complementary interlocking features along the mating surfaces (e.g., rims of mold cavities 16 and 92), so that when mold portions 14 and 90 come together, they can be self-aligned to form the spherical cavity. Retaining member 96 may have features on its mating surfaces (e.g., the rim of retaining cavity 98) that can complementarily interlock with mold portion 14, and can be substantially the same as the interlocking features on mold portion 90. These interlocking features can adopt various shapes and forms, including, but are not limited to, pins and holes, triangular or step tooth forms, oscillating lines or curves such as sinusoidal waves, and combinations thereof.

Two or more (e.g., 3, 4, 5, 6, 8, 10, 20, 50, or more) mold portions and retaining members may be incorporated in or on two or more mold platens and configured in linear or two-dimensional arrays of A×B where A and B are independent integers of 2 to 20. Mold portions 90 and retaining members 96 may be affixed to separate platens that can move independently of each other, or, when affixed to common mold platens 124, may be arranged in separate arrays or in interleaving arrays. FIG. 21 illustrates another example of mold platen 118 featuring a 2×2 array of mold portions 14, which are connected to channel 75 via a runner system 150, so that flowable materials enters all mold portions 14 simultaneously. FIG. 22 illustrates another example of mold platen 124 featuring a corresponding 2×2 array of mold portions 90 which are connected to channel 95 via runner system 152, and a corresponding 2×2 array of retaining members 96 arranged apart from mold portions 90. FIGS. 23 and 24 illustrate a further example of mold platens 118 and 124, featuring an array of mold portions 90 interleaved with retaining members 96.

FIG. 12 illustrates molding device 200 at one stage of molding, in which inner rod 106 of cylinder 12 may be retracted to bring mold platen 124 towards mold platen 118, so that mold portion 14 is in contact with retaining member 96. As such, mold platens 118 and 124, as well as mold portion 14 and retaining member 96, are in a closed position. FIG. 13 illustrates the mating of mold portion 14 with retaining member 96 at mating surfaces 18, which forms a first portion of void 20 (e.g., being substantially hemispherical) between mold cavity 16 and component 10. Mold portion 14 may have one or more (e.g., 2, 3, 4, 5, 6, or more) supporting members 28 (e.g., retractable pins) extended into void 20 and engaged with component 10. Component 10 may be held in a predetermined position (e.g., one substantially concentric to mold cavity 16) by retaining cavity 98 alone or in cooperation with supporting members 28. Mold portion 14 may further have at least one vent gap 27 formed by vent pin 24 and through bore 26. Injection nozzle 30 may dock at injection gate 29 formed by portions 29 a and 29 b (see FIGS. 10 and 11) to deliver flowable material 32 under pressure through channel 75 into the first portion of void 20.

FIG. 14 illustrates another stage of the molding process, where fronts 40 of material 32 flow over the portion of component 10 exposed to the first portion of void 20 as material 32 fills the first portion of void 20. Mold portion 14 and retaining member 96 may remain in contact (i.e., closed) during the injection, or separate from each other to form a gap 38 as disclosed herein. After a first sufficient amount of material 32 has entered the first portion of void 20 (e.g., after a predetermined amount of time, depending on injection speed of material 32, has lapsed), supporting members 28, if applied, may be removed (e.g., pins retracted) to allow material 32 fill up the entire first portion of void 20, as illustrated in FIG. 15. Trapped gas may exit mold cavity 16 through gap vent 27 around vent pin 24 incorporated in mold portion 14, or by way of vent cavity 19 together with excess material 32. The injection may be terminated by way of plunger 72 as illustrated in FIG. 7, which also ensures that the first portion of void 20 is completely filled with material 32. Gap 38, if present, may be closed as disclosed herein. Gap 38 may be created and closed by moving one or both of mold platens 118 and 124, by incorporating spring plates between mold portion 14 and mold platen 118 and/or between retaining member 96 and mold platen 124, or by other means known to one skilled in the art of mechanical engineering.

Material 32 is allowed to solidify in mold cavity 16 for another predetermined amount of time (depending at least in part on gel time of material 32) and form a first portion 11 of the desired layer 15. Then, as FIG. 16 illustrates, inner rod 106 of cylinder 102 may be extended to separate mold platen 124 and retaining member 96 from mold platen 118 and mold portion 14, respectively. The extension of inner rod 106 may be greater than the radius of component 10, optionally less than 2 inches, less than 1 inch, or less than the diameter of component 10. As such, mold platens 118 and 124, as well as mold portion 14 and retaining member 96, are in a second open position. The adhesion of molded portion 15 to mold portion 14 and to component 10 may be sufficient such that the unmolded portion (i.e., the lower portion) of component 10 is disengaged from retaining member 96, and the partially molded golf ball product (i.e., the top portion) is now retained by mold portion 14. Disengagement of component 10 from retaining member 96 may be facilitated by active ejection means. In one example, one or more retractable members (e.g., retractable pins) may be incorporated in retaining member 96. Extension of such mechanical members into retaining cavity 98 can drive out component 10. In another example, optional hydraulic or pneumatic suction applied at through openings in retaining cavity 98 for retaining component 10 may be reversed into positive pressure capable of expelling component 10 out of retaining cavity 98.

At the second open position, mold platen 124 may be re-aligned (e.g., horizontally shifted) with respect to mold platen 118 so that mold portion 14 is aligned to mold portion 90 (e.g., vertical alignment) for mating. The translational movements of mold platen 124 may be effected by manual, mechanical, hydraulic, and/or pneumatic means as disclosed herein. Upon proper alignment, inner rod 106 of cylinder 102 may be retracted again to bring mold platen 124 toward mold platen 118, so that mold portion 14 now contacts mold portion 90, as illustrated in FIG. 17. As such, mold platens 118 and 124, as well as mold portions 14 and 90, are in a second closed position. FIG. 18 illustrates the mating of mold portions 14 and 90 at mating surfaces 18, which forms a second portion of void 20 (e.g., being substantially hemispherical) between mold cavity 92 and component 10. Mold portion 90 may have one or more (e.g., 2, 3, 4, 5, 6, or more) supporting members 28 (e.g., retractable pins) extended into void 20 and engaged with component 10. Mold portion 90 may further have at least one vent gap 27 formed by vent pin 24 and through bore 26. Injection nozzle 30 may dock at injection gate 29 formed by portions 29 a and 29 c (see FIGS. 10 and 11) to deliver flowable material 32 under pressure through channel 95 into the second portion of void 20.

FIG. 19 illustrates another stage of the molding process, where fronts 40 of material 32 flow over the portion of component 10 exposed to the second portion of void 20 as it is being filled. Mold portions 14 and 90 may remain in contact (i.e., closed) during the injection, or separate from each other to form a gap 38 as disclosed herein. After a second sufficient amount of material 32 has entered the second portion of void 20 (e.g., after a predetermined amount of time, depending on injection speed of material 32, has lapsed), supporting members 28, if applied, may be removed (e.g., pins retracted) to allow material 32 fill up the entire second portion of void 20, as illustrated in FIG. 20. Trapped gas may exit mold cavity 92 through gap vent 27 around vent pin 24 incorporated in mold portion 90, or by way of vent cavity 91 together with excess material 32. The injection may be terminated by way of plunger 72 as illustrated in FIG. 7, which also ensures that the second portion of void 20 is completely filled with material 32. Gap 38, if present, may be closed as disclosed herein. Gap 38 may be created and closed by moving one or both of mold platens 118 and 124, by incorporating spring plates between mold portion 14 and mold platen 118 and/or between mold portion 90 and mold platen 124, or by other means known to one skilled in the art of mechanical engineering.

Material 32 is allowed to solidify in mold cavity 90 for another predetermined amount of time (depending at least in part on gel time of material 32) and form a second portion 13 of the desired layer 15. The second molded portion 13 may be fused to or adhered with the first mold portion 11, together forming the molded layer 15. After molded layer 15 has been substantially cured, inner rod 106 of cylinder 102 may be extended again separate mold platen 124 and mold portion 90 from mold platen 118 and mold portion 14, respectively. The extension of inner rod 106 may be greater than the radius of component 10, optionally less than 2 inches, or less than the diameter of component 10. As such, mold platens 118 and 124, as well as mold portion 14 and retaining member 96, are now in a third open position. The molded golf ball product may be released from mold portions 14 and 90 passively due to one or more mold releasing agents applied to inner surfaces 22 of mold cavities 16 and 92 or incorporated in molded layer 15. Active means may be used to facilitate mold release, such as the extension of supporting members 28 (e.g., retractable pins) into mold cavities 16 and 92, hydraulic or pneumatic suction via robotic arms, and other means known to one skilled in the art. To easy the removal of the molded golf ball products from mold portions 90, mold platen 124 may be transferred (e.g., moved horizontally) to a position that is vertically unobstructed by mold platen 118. Following the removal of the molded golf ball product, mold platen 128 may be transferred back to the beginning position, ready for the next molding cycle.

The separately molded portions of the desired layer may overlap continuously or at one or more discrete segments along the junction to enhance adhesion therebetween. Width of such overlapped areas (i.e., the longest surface distance on component 10 between the boundaries of two molded portions on any one great circle perpendicular to both boundaries) may be at least 0.005 inches, such as 0.01 inches, 0.015 inches, 0.02 inches, 0.025 inches, 0.03 inches, or greater, or any ranges therebetween. Thickness of the overlapped areas may be uniform to the thickness of the desired layer. Discrete segments of the overlapped areas may be the same or different in shape (e.g., projections that are circular, angular, tooth-form, triangular, square, rectangular, trapezoidal, dove-tailed, etc.), width, length (e.g., 0.01 inches, 0.02 inches, 0.05 inches, 0.1 inches, 0.5 inches, or greater, or therebetween, but less than half of the circumference of component 10), size, thickness (e.g., 0.0005 inches, 0.001 inches, 0.0015 inches, 0.002 inches, 0.0025 inches, or greater, or therebetween, but less than the thickness of the desired layer), and/or surface profile (e.g., even, uneven, spherical, wavy, other profiles of non-uniform thickness). Continuous overlaps may have similar width, thickness, and/or surface profile. The boundaries of continuous overlaps may be linear, oscillating (e.g., curved such as sinusoidal, tooth-formed, step-formed), zigzagging, wavy, or otherwise non-linear. Underlying portion of such overlapping areas may be molded on component 10 during the molding of the first portion of the layer, for example, by indentations and/or recesses fashioned along the junction of the inner surface of the retaining cavity and the mating surface of the retaining member. Molding of the second portion of the layer can form overlying portion of the overlapping areas.

The molding processes of the present disclosure may be applied to form outer core layers, intermediate layers, inner cover layers, and outer cover layers. The layer may be a continuous layer such as a spherical shell or a spherical lattice network, or a discontinuous layer having a plurality of discrete elements. The thickness of the layer may be uniform or non-uniform. FIG. 25 illustrates a component 10 covered by a lattice network 60 of a spherical octahedron formed from three intersecting bands 62 that extend along great circle paths and at right angles to each other. The bands 62 form spherical triangle openings 64 that expose portions of component 10.

Various materials may be used in conjunction with the molding apparatuses and methods disclosed herein. For purposes of the following discussion regarding materials, the term “catalyst” should be understood by one of ordinary skill in the art to include compounds which alter (e.g., increase or decrease) the rate of a particular reaction and which are not substantially consumed by themselves reacting with one or more of the necessary components of the particular reaction. For example, any compound containing an accessible and reactive amine, epoxy, or hydroxyl group that should readily react with an isocyanate group should be considered a reactant (e.g., a curing agent) and not a catalyst.

As used herein, the term “fluid” includes a liquid, a paste, a gel, a gas, or any combination thereof. It should be understood that the term “fluid-filled,” as used herein in reference to golf equipment or to a portion thereof, also includes the situation where the golf equipment, or the portion thereof, is hollow.

As used herein in reference to a golf ball, the term “core” represents the center and optional additional layer(s), such as an intermediate layer, which layer(s) is(are) disposed between the center and the cover of the golf ball.

The term “prepolymer” as used herein refers to a material containing at least one isocyanate-containing component (e.g., diisocyanate), and at least one isocyanate-reactive component (e.g., a polyol, a polyamine, an epoxy-containing compound, or mixtures thereof).

The term “quasi-prepolymer” as used herein refers to a subset of prepolymers in which the isocyanate content is at least about 13% of the weight of the prepolymer. Where prepolymers are mentioned herein, it should be understood that this includes prepolymers having an isocyanate content of less than about 13% by weight and also includes quasi-prepolymers.

The term “polyol,” as used herein, refers to a compound containing at least 2 hydroxyl groups, regardless of its molecular weight. The term “polyamine,” as used herein, refers to a compound containing at least 2 primary or secondary amine groups, regardless of molecular weight.

Materials that may be used with the invention include a first reactant including a polyisocyanate, or a prepolymer or quasi-prepolymer containing the reaction product of a polyol, polyamine, or epoxy-containing compound with at least one polyisocyanate, and a second reactant including at least one of a polyol, polyamine, or epoxy-containing compound. The reactants nay be mixed together to form a reactive mixture, which can be injected into a cavity or mold having a desired shape within a time sufficient to avoid substantial gelation or solidification. Advantageously, the polymerization, solidification, or gelation times of the reactive mixture of the present invention should typically not be more than about 60 seconds, such as more than 45 seconds, from 0.25 seconds to 30 seconds, from 0.5 seconds to 15 seconds, from 1 second to 10 seconds, or from 1 second to 5 seconds, all at ambient or elevated temperatures.

RIM, according to the present disclosure, includes any injection molding process in which two or more components are reactive upon contact and/or addition into a mold cavity, such as liquid injection molding (LIM), reinforced reaction injection molding (RRIM), and structural reaction injection molding (SRIM). Liquid injection molding occurs when the two or more components are in liquid form and includes subclasses such as micro-LIM and nano-LIM, which refer to smaller and much smaller injection volumes, respectively, as compared to most commercial processes. Reinforced RIM occurs with one or more filler materials being added to the two or more components prior to injection into the mold cavity. Structural RIM occurs where there is a preform around which the two or more components are injected within the mold cavity. The preform is generally in fiber or mesh form, but may be made from any material sufficient to substantially withstand the injection pressures typically associated with the RIM process. In SRIM, a composite material is typically formed.

In one example, each of the first and second reactable components have a viscosity not more than 20,000 cPs, such as not more than 15,000 cPs, from 25 cPs to 10,000 cPs, or from 25 cPs to 5,000 cPs, until the reactants are mixed together or the reactive mixture is injected into the cavity or mold. In another example, all the reactants, or mixtures thereof, that can be contacted to form the reactive mixture have viscosities similar to those of the first and second reactants. In yet another example, each reactant has a viscosity of not more than 5,000 cPs at a temperature of about 150° F. In a further example, the mixture is injected into the mold or cavity at an injection pressure of not more than 2,500 psi.

The first, or isocyanate-containing, reactant can include any isocyanate-functional monomer, or a dimeric or multimeric adduct thereof, prepolymer, quasi-prepolymer, or mixture thereof. The isocyanate-functional compounds may include monoisocyanates or polyisocyanates, which include any isocyanate functionality of two or more. Any polyisocyanate available to one of ordinary skill in the art is suitable for use according to the invention. Suitable isocyanate-containing components include diisocyanates having the generic structure OCN—R—NCO where R may be a cyclic, aromatic, or linear or branched hydrocarbon moiety containing 1-20 carbon atoms. The diisocyanate may contain one or more phenyl groups or one or more cyclic groups. When multiple aromatic or cyclic groups are present, linear and/or branched hydrocarbons containing 1-10 carbon atoms can be present as spacers between the aromatic or cyclic groups. In some cases, the cyclic or aromatic group(s) may be substituted at the 2-, 3-, and/or 4-positions, or at the ortho-, meta-, and/or para-positions, respectively. Substituted groups may include, but are not limited to, halogens; primary, secondary, or tertiary hydrocarbon groups, or a mixture thereof. Other suitable isocyanate-containing compounds or the polyisocyanates include higher functional adducts of the above diisocyanates, as well as triisocyanates and higher functional isocyanates that are not adducts of diisocyanates, and mixtures thereof. Exemplary polyisocyanates include, but are not limited to, straight or branched aliphatic diisocyanates containing from about two to forty carbons, such as ethylene diisocyanate, propylene isocyanates (e.g., propylene-1,2-diisocyanate), tetramethylene isocyanates (e.g., tetramethylene-1,4-diisocyanate), hexamethylene diisocyanates (e.g., 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate (TMDI), and the like), dodecane-1,12-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate (H₁₂MDI), 2,4,4-trimethylene diisocyanate, and the like; diisocyanates containing cyclic groups, such as cyclobutane-1,3-diisocyanate, cyclohexyl diisocyanates (e.g., cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, methyl cyclohexylene diisocyanate (H₆XDI), isophorone diisocyanate (IPDI), and the like); diisocyanates containing aromatic groups, such as 4,4′-diphenylmethane diisocyanate (MDI), polymeric MDI, carbodiimide-modified liquid MDI, p-phenylene diisocyanate (PPDI), m-phenylene diisocyanate (MPDI), toluene diisocyanate (TDI), 3,3′-dimethyl-4,4′-biphenylene diisocyanate (TODI), naphthalene diisocyanate (NDI), xylylene diisocyanate (XDI), paratetramethylxylylene diisocyanate (p-TMXDI), meta-tetramethylxylylene diisocyanate (m-TMXDI), tetracene diisocyanate, napthalene diisocyanate, anthracene diisocyanate, and the like; trimerized isocyanurates of any polyisocyanate or mixtures thereof, such as the isocyanurate of TDI, the isocyanurate of HDI, and the like; dimerized uretdiones of any polyisocyanate or mixtures thereof, such as the uretdione of TDI, the uretdione of HDI, and the like; and mixtures thereof. Polyisocyanates are known to those of ordinary skill in the art as having more than one isocyanate group, e.g., di-, tri-, and tetraisocyanate. In one example, the polyisocyanate includes MDI, PPDI, MPDI, TDI, or a mixture thereof. In another example, the polyisocyanate is completely free of m-TMXDI. It should be understood that, as used herein, the term “MDI” includes 4,4′-diphenylmethane diisocyanate, polymeric MDI, carbodiimide-modified liquid MDI, and mixtures thereof.

Typically, the amount of the isocyanate-containing reactant is determined in relation to the amount of the second reactant present in the reactive mixture. In one example, the ratio of the first isocyanate-containing reactant to the second, or isocyanate-reactive, reactant is from 0.02:1 to 10:1, such as from 2:1 to 1:2, from 1.5:1 to 1:1.5, or from 1.1:1 to 1:1.1. In one example, the first isocyanate-containing reactant may have an NCO content of 14% or less by weight, such as no greater than 7.5%, from 2.5% to 7.5%, or from 4% to 6.5%. In another example, the first isocyanate-containing reactant may have an NCO content of greater than 14% by weight. The first isocyanate-containing reactant may be a prepolymer of “low free monomer,” understood by one of ordinary skill in the art to have lower levels of “free” isocyanate monomers (e.g., 0.1% or less by weight). Prepolymers containing low free isocyanate monomers (e.g., Low Free Monomer MDI, Low Free Monomer TDI, Low Free Monomer PPDI, or mixtures thereof) are less toxic, result in polymers that are uniform and/or exhibit improved elastomeric properties.

The second reactant may include at least one polyamine, polyol, epoxy-containing compound, or a mixture thereof. In one example, the second reactant includes at least one polyamine. Suitable polyamines include, but are not limited to, tetrahydroxypropylene ethylenediamine; 3,5-dimethylthio-2,4-toluenediamine and isomers thereof, such as 3,5-dimethylthio-2,6-toluenediamine or ETHACURE™ 300, commercially available from Albermarle Corporation of Baton Rouge, La.; 3,5-diethyltoluene-2,4-diamine and isomers thereof, such as 3,5-diethyltoluene-2,6-diamine; 1,4-bis-(sec-butylamino)-benzene and isomers thereof, such as 1,2-bis-(sec-butylamino)-benzene; 1,2-bis-(sec-butylamino)-cyclohexane and isomers thereof, such as 1,4-bis-(sec-butylamino)-cyclohexane; 4,4′-bis-(sec-butylamino)-diphenylmethane and derivatives thereof, 4,4′-bis-(sec-butylamino)-dicyclohexylmethane and derivatives thereof, trimethylene glycol di-p-aminobenzoate; polytetramethyleneoxide-di-p-aminobenzoate; N,N′-dialkyldiamino diphenyl methane; p,p′-methylene dianiline (MDA); m-phenylenediamine (MPDA); 4,4′-methylene-bis-(2-chloroaniline) (MOCA); 4,4′-methylene-bis-(2,6-diethylaniline); 4,4′-methylene-bis-(3-chloro-2,6-diethylaniline); 4,4′-diamino-3,3′-diethyl-5,5′-dimethyldiphenylmethane; 2,2′,3,3′-tetrachloro-diaminodiphenylmethane; 4,4′-dicyclohexylmethane diamine; m- or p-phenylenediamine; 1,4-cyclohexyl-bis-(methylamine) and isomers thereof, such as 1,4-cyclohexyl-bis-(methylamine); 2-methylpenatmethylene diamine; diaminocyclohexane; triisopropanolamine; diethylene triamine; triethylamine tetramine; tetraethylene pentamine; isomers of propylenediamine, such as 1,3-propylenediamine; dialkylaminopropylamines, such as dimethylaminopropylamine, diethylaminopropylamine, and the like, and mixtures thereof; imido-bis-propylamine; diethanolamine; triethanolamine; diisopropanolamine; isophoronediamine; and mixtures thereof. Suitable polyamines, which can include both primary and/or secondary amines, may have molecular weights of 64-4,000 g/mol.

Other suitable polyamines include those having the general formula:

where n and m are the same or different values of 0, 1, 2, or 3, Y is a divalent radical chosen from 1,2-cyclohexyl, 1,3-cyclohexyl, 1,4-cyclohexyl, o-, m-, or p-phenylene, or the like, or a combination thereof.

Suitable polyols include any polyol, and mixture thereof, available to one of ordinary skill in the art. Examples include ethylene glycol; diethylene glycol; propylene glycol; dipropylene glycol; polyether polyol such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol (M_(n)≦4,000 g/mol), and the like, and mixtures thereof; 1,3-bis(2-hydroxyethoxy)benzene; 1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene; 1,3-bis-{2-[2-(2-hydroxyet-ho-xy)ethoxy]ethoxy}benzene; 1,3-butanediol and isomers thereof, such as 1,4-butanediol, 2,3-butanediol, and the like, and mixtures thereof, 1,5-pentanediol; 1,6-hexanediol; o-phthalate-1,6-hexanediol; resorcinol-di-(β-hydroxyethyl)ether and its derivatives; hydroquinone-di-(β-hydroxyethyl)ether and its derivatives; trimethylol propane; hydroxy-terminated polybutadiene (including partially/fully hydrogenated derivatives); polyester polyol, such as polycaprolactone polyol; polycarbonate polyol; or mixture thereof.

Polyether polyol may have the generic structure:

where R₁ and R₂ are the same or different straight or branched hydrocarbon chains, each containing 1-20 carbon atoms, and n is 1-45. Examples include, but are not limited to, polytetramethylene ether glycol (PTMEG), polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG), poly(oxyethylene-oxypropylene)glycol copolymers, and mixtures and copolymers thereof. The hydrocarbon chain can have saturated and/or unsaturated bonds and/or substituted and/or unsubstituted aromatic and/or cyclic groups.

Polyester polyols may have the generic structure:

where R₁ and R₂ are the same or different straight or branched hydrocarbon chains, each containing 1-20 carbon atoms, and n is 1-25. Suitable polyester polyols include, but are not limited to, polyethylene adipate glycol, polypropylene adipate glycol, polybutylene adipate glycol, poly(ethylene adipate-propylene adipate)glycol, poly(hexamethylene adipate)glycol, and mixtures and copolymers thereof. The hydrocarbon chain can have saturated and/or unsaturated bonds, and/or substituted and/or unsubstituted aromatic and/or cyclic groups.

Polyester polyols also include polycyclic ester polyols, such as polycaprolactone polyols having the generic structure:

where R₁ is a straight chain or branched hydrocarbon chain containing 1-20 carbon atoms, and n is the same or different chain lengths of 1-20. Suitable polycaprolactone polyols include, but are not limited to, 1,6-hexanediol-initiated polycaprolactone, diethylene glycol-initiated polycaprolactone, trimethylol propane-initiated polycaprolactone, neopentyl glycol-initiated polycaprolactone, 1,4-butanediol-initiated polycaprolactone, PTMEG-initiated polycaprolactone, and mixtures thereof. The hydrocarbon chain can have saturated and/or unsaturated bonds, and/or substituted and/or unsubstituted aromatic and/or cyclic groups.

Polycarbonate polyols may have the generic structure:

where R₁ may include at least one linear or branched hydrocarbon chain, which may have saturated and/or unsaturated bonds and/or substituted and/or unsubstituted aromatic and/or cyclic groups (e.g., predominantly bisphenol A units —(P—C₆H₄)—C(CH₃)₂-(p-C₆H₄)— or derivatives thereof), and the chain length, n, is 1-20. Suitable polycarbonates include, but are not limited to, poly(phthalate carbonate)glycol, poly(hexamethylene carbonate)glycol, polycarbonate glycols containing bisphenol A, or mixtures or copolymers thereof.

Other suitable polyols have the following general chemical structure:

where n and m are the same or different values of 0, 1, 2, or 3, and X is o-phenylene, m-phenylene, p-phenylene, 1,2-cyclohexyl, 1,3-cyclohexyl, 1,4-cyclohexyl, or mixtures thereof.

The second reactant may contain at least one compound having a molecular weight of at least about 400 g/mol, such as from about 200 g/mol to about 4,000 g/mol, or not more than about 400 g/mol, or about 18 g/mol to 600 g/mol. The second reactant may contain at least two compounds, a first compound having a molecular weight of not less than about 400 g/mol, such as from about 200 g/mol to about 4000 g/mol, and a second compound having a molecular weight of not more than about 400 g/mol, or from about 18 g/mol to 600 g/mol. It should be understood that molecular weight, as used herein, is the absolute number average molecular weight and would be understood as such by one of ordinary skill in the art.

Generally, when the second reactant contains a compound with a molecular weight of not less than about 400 g/mol, the compound may be considered to form a “soft segment” of the resulting polymer material. The soft segment may be present in an amount of about 40% to 95%, such as 50% to 90%, or 60% to 85%, based on the total weight of the polymer.

Epoxy-containing compounds may have the general formula:

wherein R₁ and R₂ are the same or different radicals chosen from hydrogen and organic groups including linear or branched chain alkyl, aryl, hydrocarbyloxy, and carbocyclic groups, and mixtures thereof. Epoxy-containing compounds may have two or more epoxy groups, such as:

wherein R₁ is defined above. Such diepoxy compounds include (2,2-bis[4-(2′3′epoxy propoxy)phenyl]propane) (e.g., diglycidyl ether of bisphenol A, or DGEBA), of the formula:

and higher molecular weight homologs, such as those of the formula:

where n is from 0.5 to about 2.5, such as about 0.15 for D.E.R. 331 epoxy resin (epoxy equivalent weight range of 182-192 and viscosity of 11,000-14,000 cPs). In low melting point solid resins, n is ≧2.5. In high melting point solid resins, n may be as high as 18. Other epoxy-containing compounds include epoxy-novolac resins under the trade name D.E.N. (400 series), such as D.E.N. 431, D.E.N. 438 and D.E.N. 439, available from Dow Chemical Co., low viscosity polyglycol epoxy resins under the trade name D.E.R. (700 series), such as D.E.R. 732 and D.E.R. 736, and EPON™ epoxy resins available from Shell.

As used herein, the phrase linear, straight, or branched hydrocarbon chain include, but are not limited to, substituted or unsubstituted acyclic carbon-containing radicals, such as alkyl groups or alkylene chains of 1-30 carbon atoms. Examples include lower alkyls such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, and upper alkyls. Such hydrocarbon chains may contain various substituents in which one or more hydrogen atoms have been replaced by functional groups such as, without limitation, hydroxyl, amino, carboxyl, amide, ester, ether, halogen (fluorine, chlorine, bromine, or iodine), siloxanes, and sulfonic amides.

As used herein, substituted and/or unsubstituted carbocyclic radicals of 1-20 twenty carbon atoms means cyclic carbon-containing compounds, including but not limited to cyclopentyl, cyclohexyl, and a combination thereof.

The polyols, polyamines, and epoxy-containing compounds can include one or more saturated, unsaturated, aromatic, and/or cyclic groups. Additionally, the polyols, polyamines, and epoxy-containing compounds can include one or more halogen groups. Also, a single polyol, polyamine, or epoxy-containing compound may be used, as well as a blend or mixture thereof.

One or more catalysts may optionally be used to alter (e.g., accelerate, facilitate, or slow down) the reaction between the isocyanate-containing component and the isocyanate-reactive component (e.g., the polyol, polyamine, and/or epoxy-containing compound). The catalyst may be contained separately from all other components or added to one or more other components, such as the isocyanate-containing component or the isocyanate-reactive component, to form a mixture. Suitable catalysts include, but are not limited to, tin catalysts, such as dibutyltin dilaurate; amine catalysts, such as trialkylamine (e.g., triethylenediamine, triethylamine, tributylamine, or a mixture thereof); organic acids, such as acetic acid, oleic acid, or a mixture thereof; delayed catalysts, such as POLYCA™ SA-1, POLYCAT™ SA-102, and the like, or a mixture thereof; or combinations thereof. Catalyst is added in an amount sufficient to catalyze the reaction of the components in the reactive mixture, such as about 0.001% to 3%, based on the total weight of the first and second reactants.

Fillers added to one or more layers of the golf equipment, e.g., a golf ball, typically include processing aids or compounds to affect rheological and mixing properties, specific gravity (i.e., density-modifying fillers), modulus, tear strength, reinforcement, and/or the like. A density-adjusting filler may be used to control moment of inertia, and thus initial spin rate of the ball and spin rate decay. Fillers are typically polymeric or inorganic in nature, and, when used, are typically present in an amount from about 0.1 to 50 weight percent of the layer or portion in which they are included. Any suitable filler available to one of ordinary skill in the art may be used. Exemplary fillers include, but are not limited to, precipitated hydrated silica; clay; talc; glass fibers; aramid fibers; mica; calcium metasilicate; barium sulfate; zinc sulfide; lithopone; silicates; silicon carbide; diatomaceous earth; carbonates such as calcium carbonate and magnesium carbonate; metals such as titanium, tungsten, aluminum, bismuth, nickel, molybdenum, iron, copper, boron, cobalt, beryllium, zinc, and tin; metal alloys such as steel, brass, bronze, boron carbide whiskers, and tungsten carbide whiskers; metal oxides such as zinc oxide, iron oxide, aluminum oxide, titanium oxide, magnesium oxide, and zirconium oxide; particulate carbonaceous materials such as graphite, carbon black, cotton flock, natural bitumen, and cellulose flock; micro balloons such as glass and ceramic; fly ash; cured, ground rubber; or combinations thereof. Additives such as accelerators (e.g., tetra methylthiuram), processing aids, processing oils, plasticizers, colorants (e.g., dyes and/or pigments), as well as other additives well known to the ordinary-skilled artisan, may also be used in amounts sufficient to achieve the purpose for which they are typically used.

Each reactant may include at least two sets of precursor components that can be reacted to form at least two different polymers of an interpenetrating polymer network (IPN), wherein at least one of the polymers is crosslinked. Any of the at least two component sets may include a mixture of precursor components that are sufficiently non-reactive to each other within the mixture, such that the different sets of precursor components, when placed in contact with each other, can still form the IPN. Suitable IPN compositions include those described in co-pending U.S. Patent Publication No. 2002/0187857, the disclosure of which is incorporated herein by express reference in its entirety.

The formed golf ball product may optionally include a foamed material. This foamed material may advantageously be made using the materials as detailed herein. Suitable components of the foamed material may include those described in U.S. Pat. No. 6,386,992, the disclosure of which is incorporated herein by reference in its entirety. For example, an IPN can be foamed and used to form a golf ball product, or a portion thereof. The curing agent for the foamed material may also include water.

When the golf ball product contains multiple layers, a surface treatment between any two adjoining layers may be effected to improve the adhesion between those layers. The surface treatment may include mechanical abrasion (e.g., sandblasting); plasma treatment (e.g., at atmospheric pressure); corona treatment; flame treatment; wet chemical surface modification; application of adhesives or adhesion promoters (e.g., EASTMAN 343-1, 343-3, and 515-2 from Eastman Chemical Co. of Kingsport, Tenn., BAYER 8173, U42, U53, and 140AQ from Bayer Corp. of Pittsburgh, Pa., RICOBOND from Ricon Resins, Inc. of Grand Junction, Colo., WITCOBOND from Witco Corp. of Greenwich Conn.); and the like; or a combination thereof. Advantageously, the surface treatment may be effected as described in U.S. Pat. No. 6,315,915, the disclosure of which is incorporated herein by reference in its entirety.

The resultant golf balls may have a dimple coverage of greater than about 60%, such as greater than 65%, or greater than 70%. The golf balls may have a cover material hardness of 15 Shore A to 85 Shore D, and/or a flexural modulus (measured according to ASTM D6272-98) of greater than about 500 psi (3.4 MPa). The flexural modulus of reaction injection molded golf ball product, or portion thereof, can be about 300,000 psi (2.1 GPa) or less, such as about 5,000 psi (34 MPa) or less. The golf balls may have a coefficient of restitution of about 0.7 or greater, such as 0.75 or greater, or 0.78 or greater, at an initial velocity of 125 ft/s. The golf balls may have an Atti compression of about 40 or greater, such as 50 to 120, or 60 to 100.

All patents and patent applications cited in the foregoing text are expressly incorporated herein by reference in their entirety.

The present disclosure is not to be limited in scope by the specific examples described herein, since these examples are intended solely as illustrations of various aspects of the disclosure, which includes different materials, compositions, formulations, and steps of molding methods. The different aspects disclosed herein may be applied singly, independently, in combinations of two or more thereof, in various sequences or orders, or overlap in space and/or time. Any equivalent examples understood by one skilled in the art are intended to be within the scope of this disclosure. Indeed, various modifications of the disclosure in addition to the examples shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. 

1. A method of molding a layer formed of at least one flowable reactive material having a gel time of 10 seconds or less about a golf ball product, comprising: holding a first portion of the golf ball product in a retaining cavity of a retaining member to expose a second portion of the golf ball product; positioning the exposed second portion of the golf ball product in a first mold cavity of a first mold portion; injecting the reactive material at a mating surface between the retaining member and the first mold portion into the first mold cavity to mold a first portion of the layer over the second portion of the golf ball product; disengaging the retaining member from the golf ball product to expose the first portion thereof while holding the molded first portion of the layer by the first mold portion; positioning the exposed first portion of the golf ball product in a second mold cavity of a second mold portion; injecting the reactive material at a mating surface between the first and second mold portions into the second mold cavity to mold a second portion of the layer over the first portion of the golf ball product; and removing the golf ball product with the molded layer from the first and second molded portions.
 2. The method of claim 1, wherein the holding the golf ball product in the retaining cavity comprises snuggly fitting the golf ball product in the retaining cavity that is substantially hemispherical and has a radius substantially equal to that of the golf ball product.
 3. The method of claim 1, wherein the holding the golf ball product in the retaining cavity comprises snuggly fitting the golf ball product in the retaining cavity that is substantially hemispherical and free of openings.
 4. The method of claim 1, wherein the retaining member comprises at least one through opening in communication with the retaining cavity for air or inert gas to flow into or out of the retaining cavity.
 5. The method of claim 4, wherein a negative or positive pressure is applied to the retaining cavity via the at least one through opening during the step of holding the golf ball product in the retaining cavity or the step of disengaging the retaining member from the golf ball product, respectively.
 6. The method of claim 1, wherein the disengaging the retaining member from the golf ball product comprises: extending one or more retractable elements into the retaining cavity; and expelling the golf ball product out of the retaining member.
 7. The method of claim 1, wherein the positioning the second portion of the golf ball product in the first mold cavity comprises: mating the first mold portion with the retaining member at a mating surface; extending one or more supporting members through the first mold portion into the first mold cavity to engage with the second portion of the golf ball product; and holding the golf ball product with the supporting members and the retaining member.
 8. The method of claim 1, wherein the first mold portion comprises at least one through opening in communication with the first mold cavity for air or inert gas to flow into or out of the first mold cavity.
 9. The method of claim 8, wherein a negative or positive pressure is applied to the first mold cavity via the at least one through opening during the step of holding the molded first portion of the layer or the step of removing the molded layer from the mold portions, respectively.
 10. The method of claim 1, wherein the positioning the first portion of the golf ball product in the second mold cavity comprises: mating the first mold portion with the second mold portion at a mating surface; extending one or more supporting members through the second mold portion into the second mold cavity to engage with the first portion of the golf ball product; and holding the golf ball product with the supporting members and the first mold portion.
 11. The method of claim 1, wherein the second mold portion comprises at least one through opening in communication with the second mold cavity for air or inert gas to flow into or out of the second mold cavity.
 12. The method of claim 11, wherein a negative or positive pressure is applied to the second mold cavity via the at least one through opening during the step of holding the molded second portion of the layer or the step of removing the molded layer from the mold portions, respectively.
 13. The method of claim 1, wherein the retaining member is stationary, or mobile but independent of the second mold portion.
 14. The method of claim 1, wherein at least one of the retaining member, the first mold portion, and the second mold portion is detachably affixed to at least one of the first and second mold platens.
 15. The method of claim 1, wherein the layer is an outer cover layer, an inner cover layer, an intermediate layer, a dimpled layer, a lattice network layer, or a discontinuous layer comprising a plurality of discrete elements.
 16. The method of claim 1, wherein the layer has a thickness of 0.03 inches or less.
 17. The method of claim 1, wherein the forming the layer comprises overlapping the first and second molded portions at one or more locations by a width of 0.005 inches or greater.
 18. A method of molding a layer formed of at least one reaction injection molding material about each golf ball product in an A×B array of golf ball products where A and B are independent integers of at least 2, comprising: holding a first portion of each golf ball product in an retaining cavity of an A×B array of retaining member to expose a second portion of each golf ball product; positioning the exposed second portion of each golf ball product in a first mold cavity of an A×B array of first mold portions; molding a first portion of the layer from a reaction injection molding material over the second portion of each golf ball product; disengaging the retaining member array from the golf ball product array to expose the first portion of each golf ball product while holding the molded first portions of the layers by the first mold portion array; positioning the exposed first portion of each golf ball product in a second mold cavity of an A×B array of second mold portions; molding a second portion of the layer from the reaction injection molding material over the first portion of each golf ball product; and removing the golf ball product with the molded layer from the first and second molded portions.
 19. The method of claim 18, wherein the retaining member array and the second mold portion array are detachably affixed to a common mold platen and interleave with each other.
 20. A method of molding a layer formed of at least one reaction injection molding material about a golf ball product, comprising: holding a bottom portion of the golf ball product horizontally in a retaining cavity of retaining member to expose a top portion of the golf ball product; positioning the exposed top portion of the golf ball product in a top mold cavity of a top mold portion; injecting the reaction injection molding material at a mating surface between the retaining member and the top mold portion into the top mold cavity to mold a top portion of the layer over the top portion of the golf ball product; disengaging the retaining member from the golf ball product to expose the bottom portion thereof while holding the molded top portion of the layer by the top mold portion; positioning the exposed bottom portion of the golf ball product in a bottom mold cavity of a bottom mold portion; injecting the reaction injection molding material at a mating surface between the top and bottom mold portions into the bottom mold cavity to mold a bottom portion of the layer over the bottom portion of the golf ball product; and removing the golf ball product with the molded layer from the first and second molded portions. 